Effectiveness of a Fourth Dose of COVID-19 Vaccine among Long-Term Care Residents in Ontario, Canada: Test-Negative Design Study

Objective:People with HIV were underrepresented in coronavirus disease 2019 (COVID-19) vaccine clinical trials. We estimated vaccine effectiveness (VE) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection for the BNT162b2, mRNA-1273, and ChAdOx1 vaccines among a population-based cohort of people with HIV in Ontario, Canada.Design:Test-negative designMethods:We identified people with HIV aged ≥19 years who were tested for SARS-CoV-2 by RT-PCR between December 14, 2020 (first availability of COVID-19 vaccines) and November 21, 2021 (pre-Omicron circulation). Outcomes included any infection, symptomatic infection, and COVID-19-related hospitalization/death. We compared the odds of vaccination between test-positive cases and test-negative controls using multivariable logistic regression with adjustment for age, sex, region, calendar time, SARS-CoV-2 test histories, influenza vaccination, comorbidities, and neighborhood-level socio-economic status. VE was derived as (1 – adjusted odds ratio) × 100%.Results:Among 21 023 adults living with HIV, there were 801 (8.3%) test-positive cases and 8,879 (91.7%) test-negative controls. 20.1% cases and 47.8% of controls received ≥1 COVID-19 vaccine dose; among two-dose recipients, 93.4% received ≥1 mRNA dose. Two-dose VE ≥7 days before specimen collection was 82% (95% confidence interval [CI] = 74–87%) against any infection, 94% (95% CI = 82–98%) against symptomatic infection, and 97% (95% CI = 85–100%) against hospitalization/death. Against any infection, VE declined from 86% (95% CI = 77–92%) within 7–59 days after the second dose to 66% (95% CI = −15–90%) after ≥180 days; we did not observe evidence of waning protection for other outcomes.Conclusion:Two doses of COVID-19 vaccine offered substantial protection against symptomatic illness and hospitalization/death in people with HIV prior to the emergence of the Omicron variant. Our findings do not support a broad conclusion that COVID-19 VE is lower among people with HIV in populations that, for the most part, are attending HIV care, taking antiretroviral medication, and are virally suppressed.

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Section: Discussionmentioning

confidence: 99%

“…Outcomes included: any RT-PCR-confirmed SARS-CoV-2 infection, RT-PCR-confirmed SARS-CoV-2 infection associated with symptomatic illness, and COVID-19-related hospitalizations and/or death [23]. For symptomatic infections, we restricted the analysis to individuals who had ≥1 symptom indicated on their laboratory requisition form.…”

Section: Methodsmentioning

confidence: 99%

Coronavirus disease 2019 vaccine effectiveness among a population-based cohort of people living with HIV

Chambers

Samji

Cooper

et al. 2022

Aids

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“…Our study considers the case where the circulating strain is Omicron (B.1.1.529) variant. The first dose of COVID-19 has been deemed ineffective against Omicron infection, but the vaccine effectiveness against second, third, and fourth doses increases and will be assumed to be 0.06, 0.39, and 0.49, respectively ( 21 , 22 ). To be more generic, the COVID-19 vaccine effectiveness in our model is defined as follows:…”

Section: The Co-circulation Modelmentioning

confidence: 99%

Mitigating co-circulation of seasonal influenza and COVID-19 pandemic in the presence of vaccination: A mathematical modeling approach

Majeed

David

Bragazzi

et al. 2023

Front. Public Health

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The co-circulation of two respiratory infections with similar symptoms in a population can significantly overburden a healthcare system by slowing the testing and treatment. The persistent emergence of contagious variants of SARS-CoV-2, along with imperfect vaccines and their waning protections, have increased the likelihood of new COVID-19 outbreaks taking place during a typical flu season. Here, we developed a mathematical model for the co-circulation dynamics of COVID-19 and influenza, under different scenarios of influenza vaccine coverage, COVID-19 vaccine booster coverage and efficacy, and testing capacity. We investigated the required minimal and optimal coverage of COVID-19 booster (third) and fourth doses, in conjunction with the influenza vaccine, to avoid the coincidence of infection peaks for both diseases in a single season. We show that the testing delay brought on by the high number of influenza cases impacts the dynamics of influenza and COVID-19 transmission. The earlier the peak of the flu season and the greater the number of infections with flu-like symptoms, the greater the risk of flu transmission, which slows down COVID-19 testing, resulting in the delay of complete isolation of patients with COVID-19 who have not been isolated before the clinical presentation of symptoms and have been continuing their normal daily activities. Furthermore, our simulations stress the importance of vaccine uptake for preventing infection, severe illness, and hospitalization at the individual level and for disease outbreak control at the population level to avoid putting strain on already weak and overwhelmed healthcare systems. As such, ensuring optimal vaccine coverage for COVID-19 and influenza to reduce the burden of these infections is paramount. We showed that by keeping the influenza vaccine coverage about 35% and increasing the coverage of booster or fourth dose of COVID-19 not only reduces the infections with COVID-19 but also can delay its peak time. If the influenza vaccine coverage is increased to 55%, unexpectedly, it increases the peak size of influenza infections slightly, while it reduces the peak size of COVID-19 as well as significantly delays the peaks of both of these diseases. Mask-wearing coupled with a moderate increase in the vaccine uptake may mitigate COVID-19 and prevent an influenza outbreak.

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“…Data on the effectiveness of these additional boosters are sparse and do not predict the duration of continued protection. Data on additional booster doses are available only for mRNA vaccines [53].…”

Section: Additional Booster Doses For Immunocompromised Peoplementioning

confidence: 99%

Recommendations for prevention of SARS-CoV-2 infection in immunocompromised patients

Tomasiewicz

Dębska‐Ślizień²,

Durlik³

et al. 2023

Hematologia

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Effectiveness of a Fourth Dose of COVID-19 Vaccine among Long-Term Care Residents in Ontario, Canada: Test-Negative Design Study

Cited by 8 publications

References 31 publications

Coronavirus disease 2019 vaccine effectiveness among a population-based cohort of people living with HIV

Coronavirus disease 2019 vaccine effectiveness among a population-based cohort of people living with HIV

Mitigating co-circulation of seasonal influenza and COVID-19 pandemic in the presence of vaccination: A mathematical modeling approach

Recommendations for prevention of SARS-CoV-2 infection in immunocompromised patients

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